Fine gauge microtubing has been made for many years by coating a surface treated copper mandrel wire with one or more suitable curable resins and subsequently removing the mandrel wire after the resin coating has been cured. In this regard, attention is directed to U.S. Pat. No. 4,051,284 issued to Ohkubo, et al. on Sept. 27, 1977, and entitled "Method for Producing Heat Resistant Synthetic Resin Tubes, " the entire content of this prior U.S. Patent being expressly incorporated by reference.
In medical applications, such as guide catheters, it is usually desirable that the hollow tube or microtube portion of the catheter have characteristics which vary over the length of the tube. Characteristics that are particularly desirable along various portions of catheter tubes include torque transmission or pushability, stiffness or flexibility, burst strength, and kink resistance. It is also necessary that the components of microtubes used in catheters be biocompatible so as not to induce thrombosis or other trauma when used.